L to R: Actress/model Kimora Lee, actor Djimon Hounsou wearing Ermenegildo Zegna, actor Emile Hirsch, actor Colin Firth wearing Ermenegildo Zegna, Livia Firth, President of Oxfam America Raymond Offenheiser wearing Ermenegildo Zegna, actress Kristin Davis, Anna Zegna and and Publisher of Vanity Fair Edward Menicheschi attend the Vanity Fair and Ermenegildo Zegna Dinner hosted by Colin & Livia Firth and Anna Zegna, in support of Oxfam America and The Green Carpet Challenge. Photo by Donato Sardella/Getty Images for VF

Lyndsay Cruz is Oxfam America’s senior advisor for public figures, working with celebrities to amplify Oxfam’s work around the world.

This past Wednesday night, Vanity Fair, Oxfam Ambassadors Colin and Livia Firth, and Italian clothing designer Ermenegildo Zegna hosted an event at the Chateau Marmont in LA to benefit Oxfam America and the Green Carpet Challenge. Anna Zegna, Vanity Fair editor Graydon Carter, and Oxfam America’s president Ray Offenheiser joined Celebrity Ambassadors  Kristin Davis, Djimon Hounsou and his wife Kimora Lee Simmons, and Emile Hirsh. Other celebrity  supporters in attendance included Mia Wasikowska, Emily Blunt, John Krasinski, Cameron Diaz, Gary Oldman, and Kenneth Branagh. (You can read more about the event in the LA Times and watch video coverage on Entertainment Tonight.)

The Green Carpet Challenge, founded by Oxfam Ambassador Livia Firth and British journalist Lucy Siegle, pairs glamour and ethics to raise the profile of sustainable style at the world’s most high profile red carpet events. Oxfam is a charitable partner of the Green Carpet Challenge.

Check out more photos from the benefit event below:

Actor Colin Firth wearing Ermenegildo Zegna, Livia Firth, actress Emily Blunt and actor John Krasinski wearing Ermenegildo Zegna attend the Vanity Fair and Ermenegildo Zegna Dinner hosted by Colin & Livia Firth and Anna Zegna, in support of Oxfam America and The Green Carpet Challenge at Chateau Marmont on February 22, 2012 in Los Angeles, California. (Photo by Charley Gallay/Getty Images for VF)

Publisher of Vanity Fair Edward Menicheschi, actress Kristin Davis and President of Oxfam America Raymond Offenheiser wearing Ermenegildo Zegna attend the Vanity Fair and Ermenegildo Zegna Dinner hosted by Colin & Livia Firth and Anna Zegna, in support of Oxfam America and The Green Carpet Challenge at Chateau Marmont on February 22, 2012 in Los Angeles, California. (Photo by Charley Gallay/Getty Images for VF)

Actress Cameron Diaz attends the Vanity Fair and Ermenegildo Zegna Dinner hosted by Colin & Livia Firth and Anna Zegna, in support of Oxfam America and The Green Carpet Challenge at Chateau Marmont on February 22, 2012 in Los Angeles, California. (Photo by Charley Gallay/Getty Images for VF)